JP6835684B2 - Exhaust valve open control program - Google Patents

Description

The present invention relates to an exhaust valve open time control program executed when the exhaust valve is switched from closed to open.

In the vehicle height control system described in Patent Document 1, when the vehicle height is higher than the target vehicle height by executing the down control program, the vehicle height is lowered by exhausting air from the air cylinder.

Japanese Unexamined Patent Publication No. 3-70615

An object of the present invention is to reduce the noise generated when the exhaust valve is switched from closed to open.

Means and effects to solve problems

When the exhaust valve opening control program according to the present invention is executed, the exhaust valve is switched from closed to open after the pressure of the air around the exhaust valve is lowered.
When the exhaust valve is switched from closed to open, the high-pressure air existing around the exhaust valve is immediately exhausted to the atmosphere (atmospheric pressure), but in that case, a loud noise is generated. It is considered that a loud noise is generated when the pressure difference between the air pressure around the exhaust valve and the atmospheric pressure is large.
On the other hand, when the control program for opening the exhaust valve is executed, the pressure of the air around the exhaust valve is lowered before the exhaust valve is switched from closed to open. As a result, the noise generated when the exhaust valve is switched from closed to open can be reduced.

It is a circuit diagram which represents the vehicle height control system including the vehicle height control ECU which stores and executes the control program at the time of opening of the exhaust valve which concerns on this invention. It is a conceptual diagram which shows the periphery of the said vehicle height control ECU. It is a figure which shows one state (suction process) when the exhaust valve opening preparation control is performed by executing the exhaust valve opening control program in the vehicle height control system. It is a figure showing another state (circulation process) of the exhaust valve opening preparation control. It is a figure which shows the other state (holding process) of the exhaust valve opening preparation control. It is a figure which shows the state which decompression control is performed in the said vehicle height control system. It is a figure which shows the state which the distribution control is performed in the said vehicle height control system. It is a figure which conceptually represents a series of control related to the said decompression control. It is a flowchart which shows the decompression control program stored in the storage part of the vehicle height control ECU. It is a flowchart which shows the start time control program stored in the said storage part. It is a flowchart which shows the end-time control program stored in the said storage part. It is a figure which shows the state which down control is performed in the said vehicle height control system. It is a figure which shows another state in which the down control is performed. It is a figure which conceptually shows a series of control which is related to the down control. It is a flowchart which shows the down control program stored in the said storage part. It is a flowchart which shows the pause control program stored in the said storage part. It is a figure for demonstrating a problem in a conventional vehicle height control system.

Embodiment of the invention

Hereinafter, a vehicle height control system including a vehicle height control ECU in which an exhaust valve opening control program according to an embodiment of the present invention is stored will be described in detail with reference to the drawings.

In this vehicle height control system, as shown in FIG. 1, a wheel side member (for example, a suspension arm that supports the wheels) and a vehicle body correspond to each of the front, rear, left, and right wheels provided in the vehicle. A suspension spring (not shown), air cylinders 2FL, FR, RL, RR as vehicle height control actuators, and shock absorbers 4FL, FR, RL, RR are provided in parallel with each other between the side members. Each of the shock absorbers 4FL, FR, RL, and RR includes an absorber main body provided on the wheel side member and an absorber piston provided on the vehicle body side member, respectively.
Hereinafter, in the present specification, when it is necessary to distinguish the air cylinder 2, the shock absorber 4, etc. by the position of the wheel, the reference numerals FL, FR, RL, RR indicating the position of the wheel are added, but the position of the wheel is attached. When it is not necessary to distinguish between the two, and when the generic name is used, the symbols FL, FR, RL, RR, etc., which represent the positions of the wheels, are omitted.

The air cylinder 2 is provided on the cylinder body 10 provided on the vehicle body side member, the diaphragm 12 fixed to the cylinder body 10, and the absorber bodies of the diaphragm 12 and the shock absorber 2 so as to be relatively immovable in the vertical direction. It includes an air piston 14, and the inside thereof is an air chamber 19 as a pressure medium chamber. The air supply / discharge in the air chamber 19 causes the air piston 14 to move relative to the cylinder body 10 in the vertical direction, whereby the absorber main body and the absorber piston are relatively moved in the vertical direction in the shock absorber 4. , The vehicle height, which is the distance between the wheel side member and the vehicle body side member, can be changed.

An air supply / discharge device 24 is connected to the air chamber 19 of the air cylinder 2 via the individual passage 20 and the common passage 22, respectively. A vehicle height control valve 26 is provided in each of the individual passages 20. The vehicle height control valve 26 is a normally closed solenoid valve that can be opened and closed by turning the solenoid on and off. The vehicle height control valve 26 allows bidirectional air flow in the open state and blocks the air flow from the air chamber 19 to the common passage 22 in the closed state, but the pressure in the common passage 22 is in the air chamber 19. When the pressure is higher than the set pressure, the flow of air from the common passage 22 to the air chamber 19 is allowed.

The air supply / exhaust device 24 includes a compressor device 30, an exhaust valve 32 which is a normally closed solenoid valve, a tank 34, a switching device 36, an intake valve 44, a relief valve 46, and the like.
The compressor device 30 includes a compressor 40 and an electric motor 42 for driving the compressor 40, and the compressor 40 is operated by driving the electric motor 42. When the discharge pressure of the compressor 40 becomes high, air is exhausted to the atmosphere through the relief valve 46.
The tank 34 accommodates air in a pressurized state, and as the amount of contained air increases, the tank pressure, which is the pressure of the contained air, increases.

The switching device 36 is provided between the common passage 22, the tank passage 48 connected to the tank 34, the suction passage 65 connected to the suction side of the compressor 40, and the discharge passage connected to the discharge side of the compressor 40. , The communication state between these is switched, and includes the first passage 50, the second passage 52, and the circuit valves 61 to 64.
As shown in FIG. 1, the common passage 22 and the tank passage 48 to which the tank 34 is connected are connected by the first passage 50 and the second passage 52 provided in parallel with each other, and the first passage 50 is connected to the first passage 50. Two circuit valves 61 and 62 are provided in series, and two circuit valves 63 and 64 are provided in series in the second passage 52. Further, the suction passage 65 connects the portion between the two circuit valves 61 and 62 of the first passage 50 to the intake side portion 40a of the compressor 40, and the discharge passage 66 connects the portion between the discharge side portion 40b of the compressor 40 and the compressor 40. , The portion of the second passage 52 between the two circuit valves 63, 64 is connected.

The circuit valves 61 to 64 are normally closed solenoid valves, and can be switched between an open state and a closed state by turning the solenoid on and off. A current is supplied to the solenoid and it is turned on to open the solenoid. Allows bidirectional air flow in the open state. No current is supplied to the solenoid, and when it is turned off, it is closed. In the closed state (solenoid OFF state), the flow of air from one side to the other side is blocked, but when the pressure on the other side becomes higher than the set pressure than the pressure on one side, one side from the other side. Allows air to flow to the side of.
The circuit valves 61 and 63 prevent the outflow of air from the tank 34 in the closed state, and the circuit valves 62 prevent the outflow of air from the common passage 22 in the closed state. Reference numeral 64 denotes a block of air supply to the common passage 22 in the closed state.

An intake valve 44 is provided between the connection portion 65s of the suction passage 65 and the atmosphere. The intake valve 44 is a check valve that closes when the air pressure at the connecting portion 65s is above atmospheric pressure and opens when it is below atmospheric pressure. When the pressure of the air in the connection portion 65s becomes lower than the atmospheric pressure due to the operation of the compressor 40, the air is sucked from the atmosphere through the filter 43 and the intake valve 44.
An exhaust valve 32 is connected to the connection portion 66s of the discharge passage 66. The exhaust valve 32 is a normally closed electromagnetic valve, and in the open state, the discharge of air from the discharge passage 66 to the atmosphere is permitted, and in the closed state, the discharge of air from the discharge passage 66 to the atmosphere is blocked. When the pressure of the air in the discharge passage 66 becomes lower than the atmospheric pressure by the set pressure or more, the supply of air from the atmosphere to the discharge passage 66 is permitted.
Further, a dryer 70 and a flow suppressing mechanism 72 are provided in series in a portion of the discharge passage 66 on the second passage side of the connecting portion 66s. The flow suppression mechanism 72 includes a differential pressure valve 72v and a throttle 72s provided in parallel with each other. The differential pressure valve 72v blocks the flow of air from the second passage side to the compressor side, and when the pressure on the compressor side becomes higher than the set pressure than the pressure on the second passage side, the air from the compressor 40 to the second passage 52 Allow the flow.

In this embodiment, the vehicle height control system is controlled by a vehicle height control ECU 80 mainly composed of a vehicle height control computer. The vehicle height control ECU 80 is capable of communicating with other ECUs and the like via CAN (Controller Area Network) 82. As shown in FIG. 2, the vehicle height control ECU 80 includes an execution unit 80c, a storage unit 80m, an input / output unit 80i, a timer 80t, and the like, and the input / output unit 80i includes a vehicle height changeover switch 88, a tank pressure sensor 90, and the like. The passage pressure sensor 91, the vehicle height sensor 93, the boarding / alighting related motion detection device 95, etc. are connected, and the communication device 96, the ignition switch 98, the vehicle speed sensor 99, etc. are connected via the CAN 82. Further, the electric motor 42 is connected via the drive circuit 100, and the exhaust valve 32, the vehicle height control valve 26, and the circuit valves 61 to 64 are connected.

The vehicle height changeover switch 88 is operated by the driver, and is operated when instructing the vehicle height to be changed to any one of L (Low), N (Normal), and H (High). .. The tank pressure sensor 90 detects the tank pressure, and the passage pressure sensor 91 is provided in the common passage 22, and when the vehicle height control valve 26 is opened, it corresponds to the vehicle height control valve 26 in the open (the tank pressure sensor 90). The cylinder pressure, which is the pressure of the air chamber 19 of the cylinder 2 (corresponding to the wheel), is detected. Further, the passage pressure, which is the air pressure of the common passage 22, is detected in the closed state of all the vehicle height control valves 26. The vehicle height sensor 93 is provided corresponding to each of the front, rear, left, and right wheels, and detects the vehicle height, which is the distance of the vehicle body side member from the wheel side member. The boarding / alighting-related motion detection device 95 detects the presence / absence of motion related to boarding / alighting, and is provided corresponding to each of a plurality of doors provided in the vehicle, and is a door open / close sensor (door open / close sensor) for detecting the opening / closing of the door. It may include a vehicle sensor) 102, a door lock sensor 103 for detecting the lock and unlock of each of a plurality of doors, and the like. The intention of getting on, getting off, and starting is estimated based on the presence or absence of door opening / closing, door locking, and unlocking operations. The communication device 96 communicates with the portable device 104 owned by the driver or the like within a predetermined communicable area, and the door may be locked or unlocked by the communication. .. The ignition switch 98 is the main switch of the vehicle. The vehicle speed sensor 99 detects the traveling speed of the vehicle.
Further, the vehicle height control system and the like in this embodiment can be operated by the electric power of the battery 110. The voltage of the battery 110 is detected by the voltage monitor 112, and the voltage monitor 112 is connected to the vehicle height control ECU 80.

In the vehicle height control system configured as described above, when the tank pressure becomes lower than the pressure increase start threshold value, the pressure increase control is performed. In the pressure increase control, air is sucked from the outside air by the compressor 40 and supplied to the tank 34 to increase the tank pressure. Further, when the tank pressure becomes higher than the depressurization start threshold value, the decompression control is performed. In the depressurization control, the exhaust valve 32 is switched from closed to open, the air in the tank 34 is exhausted to the atmosphere, and the tank pressure is reduced. The tank pressure may become higher than the depressurization start threshold value due to a high temperature after the pressure increase control is performed, for example.

On the other hand, in the vehicle height control system, when down control, which is vehicle height control for lowering the vehicle height, is performed, the circuit valves 62 and 63 are opened and the compressor 40 is started as shown in FIG. The vehicle height control valve 26 of the control target wheel is opened. Air is sucked from the air cylinder 2 of the control target wheel by the compressor 40, pressurized, and supplied to the tank 34. As a result, the vehicle height becomes low and the tank pressure becomes high. Therefore, the tank pressure may become higher than the depressurization start threshold value during the down control. In that case, the depressurization control is not performed, the compressor is stopped, and the exhaust valve 32 is as shown in FIG. Is switched from closed to open. Air is exhausted from the air cylinder 2 and the vehicle height is lowered.

However, when the exhaust valve 32 is switched from closed to open, as shown in FIG. 17, high-pressure air existing around the exhaust valve 32 is exhausted to the atmosphere (atmospheric pressure) via the exhaust valve 32. In some cases, a loud noise is generated. For example, in the down control, since the discharge side portion of the compressor 40 and the tank 34 are communicated with each other, the pressure around the exhaust valve 32 is substantially the same as the tank pressure. Further, after the pressure increase control is performed, the distribution control is performed and the circuit valve 61 is opened for the set time, so that the pressures in the intake passage 65 and the discharge passage 66 are almost the same as the tank pressure. .. Therefore, air having a pressure substantially equal to that of the tank pressure exists in the crank chamber of the compressor 40, the dryer 70, and the discharge passage 66. Then, when the exhaust valve 32 is switched from closed to open, the high-pressure air existing in the crank chamber, dryer 70, etc. of the compressor 40 is exhausted to the atmosphere through the exhaust valve 32, and a loud noise is generated. Is done. That is, it is considered that a loud noise is generated when the pressure difference between the air pressure existing in the crank chamber of the compressor 40 and the dryer 70 and the atmospheric pressure is large.
Since the flow suppression device 72, the dryer 70, and the like exist between the tank 34 and the exhaust valve 32, the air in the tank 34 is immediately released from the exhaust valve 32 when the exhaust valve 32 is switched from closed to open. It is unlikely that it will be exhausted after passing through. Therefore, it is unlikely that a loud noise is generated due to the high-pressure air stored in the tank 34 being exhausted from the exhaust valve 32.

Therefore, in this embodiment, the pressure of the air around the exhaust valve 32 is lowered before the tank pressure becomes higher than the depressurization start threshold value and the exhaust valve 32 is switched from closed to open, and the exhaust valve 32 is used. Open preparation control is performed. As described above, the exhaust valve open preparation control is performed before the exhaust valve 32 is switched from closed to open when the down control is not performed, and when the exhaust valve 32 is opened from closed during the down control. It may be done before switching to.

First, a case where the tank pressure becomes higher than the decompression start threshold value and the decompression control is performed when the down control is not performed will be described with reference to FIG. In the start control of the depressurization control, the exhaust valve opening preparation control is performed, and the exhaust valve 32 is switched from closed to open.

The decompression control program represented by the flowchart of FIG. 9 is executed at predetermined set times.
In step 1 (hereinafter abbreviated as S1; the same applies to other steps), the tank pressure PT is detected by the tank pressure sensor 90, and in S2, it is determined whether or not decompression control is in progress. When the depressurization control is not in progress, in S3, it is determined whether or not the tank pressure PT is higher than the decompression start threshold value PTh, that is, whether or not the decompression control start condition is satisfied. If the start condition is not satisfied, S1 to 3 are repeatedly executed, but if the start condition is satisfied, the determination in S3 is YES, and in S4, it is determined whether or not the down control is in progress. .. When the down control is in progress, in S5, the pause flag indicating that the down control is paused is turned ON, and S6 and subsequent steps are not executed. When the down control is in progress, the decompression control is not performed. If the determination in S4 is NO, a decompression control start command (which can also be referred to as an exhaust valve open command) is output in S6.

The start control program represented by the flowchart of FIG. 10 is executed in response to the output of the start command for decompression control. The start start control includes an exhaust valve open preparation control, an exhaust valve open control, and the like, and the exhaust valve open preparation control includes a suction step (S21 to 23), a circulation step (S24, 25), and a holding step (S26, 27) and the like are included.
In S21, the circuit valves 62 and 63 are opened and the compressor 40 is started, so that the state shown in FIG. 3 is obtained. The intake passage 65 is cut off from the tank passage 48 and communicated with the common passage 22 via a part of the first passage 50. Further, the discharge passage 66 is communicated with the tank passage 48 via a part of the second passage 52. The air in the common passage 22 and the suction passage 65 is sucked by the compressor 40 and supplied to the tank 34. The air pressure in the common passage 22 and the suction passage 65 becomes low. Then, in S22, the passage pressure PC, which is the detection value of the passage pressure sensor 91, is read, and in S23, it is determined whether or not the pressure is lower than the set passage pressure PCa. If the determination is NO, the suction step is continued, but if the determination is YES, the suction step is terminated and the circulation step is started.

In S24, the circuit valve 63 is closed, the circuit valve 64 is opened, and as shown in FIG. 4, the suction passage 64 and the discharge passage 66 are cut off from the tank passage 48, and a part of the first passage 50. It is communicated with the common passage 22 through a part of the second passage 52 and is communicated with each other. A circulation circuit 130 is formed, and air is circulated in the circulation circuit 130. Inside the circulation circuit 130, air is moved from a relatively high pressure portion (discharge passage 66) to a relatively low pressure portion (suction passage 65). The pressure of the air in the discharge passage 66 becomes low, and the pressure of the air in the suction passage 65 becomes high. Although the common passage 22 does not form the circulation circuit 130, the air pressure in the common passage 22 is substantially the same as the air pressure in the circulation circuit 130 because the common passage 22 communicates with the circulation circuit 130.
The air circulation is performed during the first set time, but when the first set time elapses, the determination in S25 becomes YES, the circulation process is terminated, and the holding process is started. The first set time is, for example, the time required for the pressure difference between the suction side and the discharge side of the compressor 40 to be small enough to suppress the sound generated when the compressor 40 is stopped.

In S26, as shown in FIG. 5, the compressor 40 is stopped. This state is maintained for the second set time. Even in the holding step (even when the compressor 40 is stopped), air is moved from the high pressure portion to the low pressure portion in the circulation circuit 130, and the pressure difference is further reduced. The second set time can be, for example, a time at which the pressure of the air inside the circulation circuit 130 can be considered to be substantially the same. When the second set time elapses, it is estimated that the pressure of the air in the discharge passage 66 becomes lower, and the pressure of the air existing in the clamp chamber of the compressor 40 and the dryer 70 becomes lower.

When the second set time elapses and the determination in S27 becomes YES, the circuit valves 62 and 64 are closed in S28, and the end processing of the exhaust valve opening preparation control is performed.
Next, in S29, the circuit valve 63 is opened and the exhaust valve 32 is opened, and the decompression control start process is performed. As shown in FIG. 6, the suction passage 65 is blocked from both the tank passage 48 and the common passage 22, and the tank passage 48 is communicated with the discharge passage 66 via a part of the second passage 52. As a result, the tank 34 and the exhaust valve 32, that is, the atmosphere are communicated with each other. Air is exhausted from the tank 34 to the atmosphere through the exhaust valve 32, so that the tank pressure becomes low.

Next, the pressure is returned to S1, but since the decompression control is in progress, the determination in S2 is YES, and in S7, it is determined whether or not the tank pressure PT is lower than the decompression end threshold PTn. The decompression end threshold value PTn is a value obtained by subtracting the set value from the decompression start threshold value PTh. While the tank pressure PT is equal to or higher than the depressurization end threshold value PTn, S1, 2, and 7 are repeatedly executed. A control end command is output.

In response to the end command, the end control represented by the flowchart of FIG. 11 is performed.
In S31, the exhaust valve 32 is closed and the circuit valve 63 is closed, so that the decompression control termination process is performed. Next, in S32, the circuit valve 61 is opened, and the distribution control is started. As shown in FIG. 7, the tank passage 48 is communicated with the intake passage 65 through a part of the first passage 50. The air in the tank 34 is supplied to the intake passage 65, the compressor 40, and the discharge passage 66. This state is maintained for the third set time, and the tank pressure is distributed to the air supply / exhaust device 24. When the third set time has elapsed, the determination in S33 becomes YES, and the circuit valve 61 is closed in S34. The third set time can be, for example, a time at which it can be estimated that the tank pressure has spread to the suction passage 65 and the discharge passage 66.

Next, a case where the tank pressure PT becomes higher than the depressurization start threshold value PTh during the down control, the exhaust valve open preparation control is performed, and the exhaust valve 32 is switched from closed to open will be described with reference to FIG. .. In this case, when the pause flag is turned ON, the pause command is output, and the pause control is performed accordingly, but the exhaust valve opening preparation control is performed in the pause control.

The down control program represented by the flowchart of FIG. 15 is executed at predetermined set times.
In S41, it is determined whether or not the pause flag is ON. If the determination is NO, the vehicle height is detected by the vehicle height sensor 93 in S42, and it is determined in S43 whether or not down control is in progress. If the down control is not in progress, it is determined in S44 whether or not the down control start condition is satisfied. For example, when the actual vehicle height, which is the actual vehicle height detected in S42, is larger than the first set value with respect to the target vehicle height, it is determined that the down control start condition is satisfied. If the determination is NO, S41 to 44 are repeatedly executed. If the start condition is satisfied and the determination is YES, a down control start command is output in S45.
In response to the start command, start control (not shown) is performed, but in this embodiment, the circuit valves 62 and 63 are opened, the compressor 40 is started, and the vehicle height control valve 26 corresponding to the controlled wheel is opened. The state shown in FIG. 12 is set. The air in the air cylinder 2 of the control target wheel is sucked by the compressor 40 and supplied to the tank 34. As a result, air is discharged from the air cylinder 2 and the vehicle height is lowered.

When the down control is started, it is determined in S46 whether or not the end condition of the down control is satisfied. The end condition is considered to be satisfied when, for example, the difference between the target vehicle height and the actual vehicle height becomes equal to or less than the second set value determined based on the dead zone or the like. If the determination is NO, the down control is continuously performed, but if the end condition is satisfied, the down control end command is output in S48.
In response to the end command, end control (not shown) is performed, but if the end condition is satisfied without turning on the pause flag in the middle, the circuit valves 62 and 63 are closed and the vehicle height control valve 26 is closed. It is closed and the compressor 40 is stopped.

On the other hand, when the pause flag is turned ON (S5), a down control pause command is output in S47. Then, in response to the pause command, the pause control program represented by the flowchart of FIG. 16 is executed.
The pause control includes a pause process (S61), an exhaust valve open preparation control (S22 to 28 *), and a restart process (S62, 63: including exhaust valve opening).
In S61, the vehicle height control valve 26 is closed as a down control suspension process. Air is prevented from flowing out from the air cylinder 2. Next, the exhaust valve opening preparation control is executed, but S22 to 27 are executed without executing S21. In this case, the down control is suspended and the exhaust valve opening preparation control is performed, and the state shown in FIG. 12 is switched to the state shown in FIG. Therefore, in S61, it is only necessary to close the vehicle height control valve 26, and it is not necessary to switch the circuit valves 62 and 63 and the compressor 40.
In the flowchart of FIG. 16, in order to facilitate understanding, S21 is described, and in S61, all down control pause processing is described. However, as described above, it is not necessary to close the circuit valves 62 and 63 and stop the compressor 40 in S61.

Then, in S22 to 27, after the exhaust valve opening preparation control is similarly executed, the down control restart processing is performed, but as the end processing of the exhaust valve opening preparation control, only the circuit valve 62 is executed in S28 *. Is closed, the exhaust valve 32 is opened, and the vehicle height control valve 26 is opened in S62. In this case, since the state shown in FIG. 5 is switched to the state shown in FIG. 13, it is not necessary to switch the circuit valve 64.
In the restarted down control, the compressor 40 is in the stopped state, and the air in the air cylinder 2 is exhausted to the atmosphere through the exhaust valve 32. As a result, the vehicle height is lowered. After that, in S63, the pause flag is turned off.

Next, since the pause flag is turned off, the determination in S41 is NO, the determination in S43 is YES, and in S46, it is determined whether or not the end condition is satisfied. S41 to 43, 46 are repeatedly executed until the end condition is satisfied, but when the end condition is satisfied, an end command is output in S48. The end control is performed in response to the end command. In this case, the vehicle height control valve 26 is closed, the circuit valve 64 is closed, and the exhaust valve 32 is closed.

Further, when the down control is terminated, the determination of S4 of the exhaust valve opening control program becomes NO. After that, decompression control is performed, and the tank pressure PT is lowered below the decompression end threshold PTn.

As described above, the exhaust valve 32 is switched from closed to open when the depressurization control is performed or when the tank pressure becomes higher than the depressurization start threshold value during the down control, but the exhaust valve 32 is closed. Exhaust valve opening preparation control is performed before switching from to open. As a result, the noise generated when the exhaust valve 32 is switched from closed to open can be reduced.

As described above, in the present embodiment, the first step is configured by S21 and the like of the start time control program (pause control program represented by the flowchart of FIG. 16) represented by the flowchart of FIG. 10 of the vehicle height control ECU 80, and S24. The second step is configured by the above, and the third step is configured by S29 (S62) and the like. In addition, the exhaust valve open control program is configured by a part of the start control program, a part of the pause control program, and the like.
Further, the suction step is carried out by executing S21 or the like, the circulation step is carried out by executing S24 or the like, and the exhaust step is carried out by executing S29 (S62) or the like.

The structure of the vehicle height control system is not limited to the above-described embodiment, and the present invention may be implemented in a mode in which various changes and improvements are made based on the knowledge of those skilled in the art, in addition to the mode described above. it can.

2: Air cylinder 24: Air supply / exhaust device 26: Vehicle height control valve 30: Compressor device 32: Exhaust valve 34: Tank 40: Compressor 48: Tank passage 50: First passage 52: Second passage 65: Suction passage 66: Discharge passage 61-64: Circuit valve 80: Vehicle height control ECU 90: Tank pressure sensor 91: Passage pressure sensor 93: Vehicle height sensor

Claimable invention

The patentable inventions will be described in the following sections.
(1) A plurality of vehicle height control actuators provided on a plurality of wheels of the vehicle and connected to a common passage, and
(a) A tank that stores air, (b) a compressor, and (c) a communication position that is provided in the middle of the discharge passage connected to the discharge side of the compressor, and a communication position that communicates with the atmosphere and a cutoff position that shuts off from the atmosphere. An exhaust valve that can be switched to and (d) a tank passage that has a plurality of solenoid valves and is connected to the tank, a suction passage that is connected to the suction side of the compressor, the discharge passage, and the above. An air supply / exhaust device provided between the common passage and a switching device capable of switching the communication state between them, and an air supply / exhaust device.
In a vehicle height control system including a vehicle height control computer that controls the air supply / exhaust device, the vehicle height control computer is used.
The first step of controlling the switching device so that the suction passage is cut off from the tank passage and communicated with the common passage, and the discharge passage communicates with the tank passage, and the compressor is activated. When,
A second step of controlling the switching device so that the tank passage is cut off from the discharge passage and the suction passage and the discharge passage are communicated with each other in the operating state of the compressor.
While the compressor is stopped, one of the common passage and the tank passage is blocked from both the suction passage and the discharge passage, and the other of the common passage and the tank passage communicates with the discharge passage. An exhaust valve opening control program for controlling the switching device so as to be able to perform the switching device and executing the third step of opening the exhaust valve.
By executing the first step, the air in the common passage and the suction passage is sucked by the compressor and supplied to the tank.
By executing the second step, a circulation circuit (closed circuit) is formed, and air is circulated by the compressor in the circulation circuit. As a result, the pressure difference between the suction side and the discharge side of the compressor becomes small.
By executing the third step, the other side of the common passage and the tank passage is communicated with the exhaust valve. As a result, air is exhausted from the other side to the atmosphere through the exhaust valve. When the other is a tank passage, the air in the tank is exhausted and the tank pressure is reduced. When the other is a common passage, the air of the vehicle height control actuator is exhausted and the vehicle height is lowered.

(2) A plurality of vehicle height control actuators provided on a plurality of wheels of the vehicle and connected to a common passage, and
(a) A tank that stores air, (b) a compressor, and (c) a communication position that is provided in the middle of the discharge passage connected to the discharge side of the compressor, and a communication position that communicates with the atmosphere and a cutoff position that shuts off from the atmosphere. An exhaust valve that can be switched to (d), a tank passage connected to the tank, a suction passage connected to the suction side of the compressor, a discharge passage, and a common passage. In a vehicle height control system including a plurality of solenoid valves and an air supply / exhaust device including a switching device capable of switching the communication state between them, the air of the tank or the vehicle height control actuator is sent to the atmosphere. It is an exhaust method to exhaust
By controlling the switching device, the suction passage is cut off from the tank passage and communicated with the common passage, the discharge passage is communicated with the tank passage, and the compressor is activated to communicate with the common passage. A suction step of sucking air from the suction passage and supplying it to the tank,
By controlling the switching device in the operating state of the compressor, the tank passage is cut off from the discharge passage, and the suction passage and the discharge passage are communicated to form a circulation circuit. In the circulation process that circulates air in
By stopping the compressor and controlling the switching device, one of the common passage and the tank passage is blocked from both the suction passage and the discharge passage, so that the common passage and the tank passage can be separated from each other. An exhaust valve opening control method including an exhaust step of communicating the other with the discharge passage and opening the exhaust valve to communicate the other with the atmosphere.
The circulation step can be executed when the passage pressure, which is the pressure of the air in the common passage, becomes lower than the set pressure in the suction step.
The exhaust step is carried out after the circulation step has been carried out for the first set time. Further, the exhaust step may include a holding step of holding the stopped state of the compressor for a second set time. When the exhaust step includes a holding step, the exhaust valve is opened after the holding step is completed.

(3) A plurality of vehicle height control actuators provided on a plurality of wheels of the vehicle and connected to a common passage, and
(a) A tank that stores air, (b) a compressor, and (c) a communication position that is provided in the middle of the discharge passage connected to the discharge side of the compressor, and a communication position that communicates with the atmosphere and a cutoff position that shuts off from the atmosphere. An exhaust valve that can be switched to (d), a tank passage connected to the tank, a suction passage connected to the suction side of the compressor, a discharge passage, and a common passage. An air supply / exhaust device equipped with a plurality of electromagnetic valves and a switching device capable of switching between these communication states.
The tank pressure, which is the pressure of the air stored in the tank, becomes higher than the first set pressure, and the pressure of the air around the exhaust valve is changed from the first set pressure before the exhaust valve is switched from closed to open. A vehicle height control system characterized by including an exhaust valve opening preparation control unit that lowers the second set pressure to a lower level.
For example, the first set pressure can be a depressurization start threshold. The second set pressure can be set to a height that can suppress the generation of a loud noise when the exhaust valve is switched from closed to open.

Claims (1)

Multiple vehicle height control actuators installed on multiple wheels of the vehicle and connected to a common passage,
(a) A tank that stores air, (b) a compressor, and (c) a communication position that is provided in the middle of the discharge passage connected to the discharge side of the compressor, and a communication position that communicates with the atmosphere and a cutoff position that shuts off from the atmosphere. A tank passage connected to the tank, a suction passage connected to the suction side of the compressor, and the discharge passage, which are provided with an exhaust valve that can be switched to and (d) a plurality of solenoid valves, are common to the tank passage. An air supply / exhaust device provided between the aisles and a switching device capable of switching the communication state between them, and an air supply / exhaust device.
In a vehicle height control system including a vehicle height control computer that controls the air supply / exhaust device, the vehicle height control computer is used.
The first step of controlling the switching device so that the suction passage is cut off from the tank passage and communicated with the common passage, and the discharge passage communicates with the tank passage, and the compressor is activated. When,
A second step of controlling the switching device so that the tank passage is cut off from the discharge passage and the suction passage and the discharge passage are communicated with each other in the operating state of the compressor.
While the compressor is stopped, one of the common passage and the tank passage is blocked from both the suction passage and the discharge passage, and the other of the common passage and the tank passage communicates with the discharge passage. An exhaust valve opening control program for controlling the switching device so as to be able to perform the switching device and executing the third step of opening the exhaust valve.

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